515 miles isn't impressive for a solar powered flight? Maybe I am naive, but this seems like quite an accomplishment to me. Perhaps you would like to pull something out of your resume that is more impressive?

The 515 miles is impressive. But compared to the size of a continent, it seems like they are bragging without merit. Kind of like how it would sounds if you heard that someone ran around the earth in 20 seconds (but they really ran around the south pole). Kind of like a less extreme example of this [xkcd.com].

Note: if you just click the FAI link, you won't see the results I'm referencing above. You have to select "DO - Open Class Gliders" in the "subclass" drop-down box, "Free Distance" in the "Type of Record" drop-down box and "World

I categorize this as "cool" in the same way a "car" that gets 150+ mpg by carrying a single passenger lying down in an egg shaped vehicle at 5 mph is "cool." Yes, it is progress that a solar powered airplane has flown. That said, there are a lot of things that don't scale, and if it can't carry cargo or people, or get there in anything approaching a reasonable time frame it is a novelty at best.

However when UAVs are approved and if this guy's decendants can carry a decent payload, regular unmanned transportation of goods with a price independant of idiots killing each other in the desert might be important to humanity even if it is slow.

If the wind happens to be cooperating, great. If not, you have to spend a lot of energy pushing that big fat blimp through the air. So sure, all the energy can go into forward movements, but it will take a lot more of it.

Your point still stands, but IMHO (and I live here) flying from Alaska to Russia in anything less robust and redundant than an airliner takes some serious cojones. That water is COLD. You don't want to ditch there in an in-flight emergency.

Crossing Knik Arm outside of Anchorage (maybe two miles wide?) is uncomfortable enough. My former employer used to cross the Arm at 600 feet, until he had an airplane lose power on take-off from Anchorage International (which is on the shores of Knik Arm). He manage

The first car sucked. The first bicycle sucked. It's a goddamn proof of concept, people. Stop shit-talking it, this is how progress is made.

The first solar aircraft was built in 1974. [wikipedia.org] This is hardly the first. By 1981, a solar powered aircraft flew 163 miles. [wikipedia.org] The fact it took 31 years to increase the range by a factor of ~3 is piss poor IMHO.

The first car sucked. The first bicycle sucked. It's a goddamn proof of concept, people. Stop shit-talking it, this is how progress is made.

The first solar aircraft was built in 1974. [wikipedia.org] This is hardly the first. By 1981, a solar powered aircraft flew 163 miles. [wikipedia.org] The fact it took 31 years to increase the range by a factor of ~3 is piss poor IMHO.

If you had read your links, you knew that the Solar Riser's solar panels needed 1.5 hours of bright sunshine, to produce enough energy to fly for 3 to 5 minutes. The Solar Impulse on the other hand, is (in theory, if the pilot would not need to sleep) able to fly non-stop. Recharging it's batteries while the sun is shining (while producing enough energy to keep flying all the time).

Its flight went over 27,000 feet, which is higher than average rain clouds (wiki says around 20,000 feet is typical). It may be able to just fly over the rainclouds. They'll still need to drive around the big storms, just like the big jets have to.

So all the people seeing this as progress, realize that in 30+ years solar panels have not improved significantly enough to be able to generate the kind of power required to move 2 people, let alone 100 or 300.

This is a nice novelty, but does not harken a new era in solar power flight until there is some fundamental improvements in solar power technology.

There's some major logistical challenges to go along with the technical challenges:
1) They need at least two pilots to spell each other (which means more weight)
2) The new plane would have to go faster - at 70kph, flying 40,000 km would take 24 days
3)